Microsoft's upgrade to Internet Explorer will be automatically pushed to desktops later this month, but a web testing firm has warned that many companies may not be ready. 

According to the IE Blog, Internet Explorer 7 will be released this month and pushed out to customers via Automatic Updates a few weeks later. 

"The final release of IE7 is fast approaching," Scott Graff, programme manager for IE7 compatibility, wrote on the IE Blog.

"It will be delivered to customers via Automatic Updates a few weeks after it is available for download. We want to ensure that you are ready."

Deri Jones, chief executive at web testers SciVisum, claimed that, although IE7 appears to be more standards-compliant than the previous release, it still contains many bugs. 

"IE7 may at first appear better and more standards-compliant than IE6 but, as it comes with almost as many bugs, overall it leaves one disappointed," he said.

"IE7 fails to catch up to where other browsers like Firefox have been for some years with CSS and HTML support. Indeed, developers will be left frustrated that important elements of CSS 2.1 are still not handled."

As Microsoft has decided to push the upgrade through Windows Update within weeks of IE7's release, many users are going to be upgraded without really being aware.

The volume of calls to corporate help desks and home-user ISPs is likely to be "a nightmare", according to Jones.

"Microsoft's failure to implement a mode in IE7 that makes it display a page as if it was IE6, and which can be triggered by code in the web page, could end up being short sighted," he said.

"This option would give web developers the ability to decide when they are ready for IE7. If a site needs a bit of a tidy up to fall in line with IE7, then it may not be convenient for a business to address that immediately.

"It is arrogant of Microsoft to expect the internet to change and fall in line with its software and not the other way around. It is an error in judgment that could come back to haunt them."